Java doesn’t support set operations directly, so nested loops have to be used to realize the operations of intersection, union, complement and etc. between text files. If there are many text files, or the file to be computed is too big to be loaded into the memory, or it is required to perform set operations according to multiple fields, the code will become even more complicated. However, with the assistance of esProc, which supports set operations…

Java doesn’t support set operations directly, so nested loops have to be used to realize the operations of intersection, union, complement and etc. between text files. If there are many text files, or the file to be computed is too big to be loaded into the memory, or it is required to perform set operations according to multiple fields, the code will become even more complicated. However, with the assistance of esProc, which supports set operations directly, Java can realize these…

The computing power of SQL for mass structured data is complete, that is to say, it is impossible to find anything that SQL cannot compute. But its support layer is too low, which can lead to over-elaborate operation in practical application.…

1. What OLAP We Need Indeed?

Category: Model

OLAP is an important constituent part of BI(business intelligence).

Understood literally, OLAP is online analytical processing, that is, users conduct analytical operation on real-time business data.

But, currently the concept of OLAP is seriously narrowed, and only it refers to operations such as conducting drilling,…

This time, we compare the sequence types of the two languages. By the terminology sequence type, we mean the data structure that is kind of a sequence of data.

In Java, we have: String, array, list(arraylist and linkedlist), set;

In Python, we have: Str, tuple, list, set;

Yes, String is one of the sequence type, because it is a sequence  of char, isn’t it? About the Sting type, we only need to…